Trail Running calendar near Mill Valley 2025-2026

Run-de-Vous is an ultramarathon event at Harvey Bear Ranch Park in San Martin, California. Runners can tackle distances including 100M, 100K, 50M, 50K, a 50M Relay (four-person teams), a marathon, and a half marathon. The course is a fast, easily managed 2-mile loop, bordered by rolling hills and di..

The SPASM Crystal Springs Trail Run takes place in Woodside, California, at Huddart Park, offering runners a scenic experience through towering redwoods, lush ferns, and trails in Huddart Park, King's Mountain, and Bear Gulch. The event features multiple distances: 8K, Half Marathon, 35K, Marathon,..

The Stevens Creek Striders Reservoir Run, held in Cupertino, California, offers a scenic trail running experience with distances of a half marathon (13.2 miles), 11K, and a 2.5-mile Lollipop Loop charity run/walk. The course features shaded single-track trails and open ridge vistas, with challenging..

The Diablo Trail Run takes place at Mount Diablo State Park, Mitchell Canyon Trailhead in Clayton, California. It offers distances of 4 miles, 10 miles, half marathon, marathon, 50K, and a Kids Run. The course ranges from a 4‑mile flat section to mountainous, scenic routes for longer distances, with..

South Hills Single Track Trail Run takes place at Calero County Park in San Jose, California. The event offers a full slate of distances: 1 mile kids run, 5K, 10K, 9 mile, half marathon, 16 mile, trail marathon, and 50K. The course blends single-track trails and dirt roads, showcasing oak trees, hil..

Garin Park XC Challenge 2025, held at Garin/Dry Creek Pioneer Regional Parks on Garin Avenue in Hayward, California, is a 5K cross-country race described as a tough yet scenic run along the Garin Park ridge. Now in its 21st year, the event is part of the Pacific Association of USA Track & Field Cros..

Berkeley Trail Adventure is an Inside Trail Racing event set in Berkeley, CA, spanning Tilden Regional Park and Wildcat Canyon. Distances offered are 50K (31 miles), 35K (21.6 miles), half marathon (13 miles), and 10K. The course blends technical dirt trails and non-technical fire roads, with about..

The Mt. Umunhum Marathon, Race to the Top and Down, is a challenging trail running event held in Almaden Quicksilver County Park, San Jose, California. This marathon features a rugged course that begins at the Hacienda Entrance and ascends to the summit of Mt.Umunhum, one of the prominent peaks in t..

The Rocky Ridge Trail Half Marathon is a challenging trail race held in the scenic Las Trampas Wilderness near San Ramon, California. Scheduled for September 20, 2025, the event features a demanding half marathon known for its tough hills and breathtaking views, offering runners a unique wilderness..

The Dick Collins Firetrails will take place in Castro Valley from Saturday 27 September 2025 to Sunday 28 September 2025. You can run between 42 and 100 kilometers.

The Pacifica Summit Run is a trail running event held at San Pedro Valley State Park in Pacifica, California. It features two race distances: a 10K and a half marathon. Runners experience scenic views from the tallest mountain on the upper San Francisco Peninsula, including stunning postcard vistas..

JP's Backyard Ultra/Hike is a grassroots ultramarathon and hike held at Skyline Wilderness Park in Napa, California. In its third year, the event features a 3.3-mile loop with 550+ feet of climbing through rocky and shaded trails. Runners and hikers may do 1 to 10 loops, starting together on the hou..

The Spartan Trail - San Jose Trail Challenge takes place in Sanborn County Park, located on the eastern slopes of the Santa Cruz Mountains near Saratoga, California. This scenic event offers three race distances: 10K, half marathon (21K), and 50K, featuring challenging, well-groomed trails with big..

The Trailblazer Race in Mountain View, CA, is an annual family-friendly event featuring 10K and 5K runs, plus a 3-mile walk along the scenic Stevens Creek Trail and Shoreline Park. The courses are fast, flat, and stroller-friendly, offering beautiful views of wildlife, salt ponds, and surrounding mo..

The Women's Headlands Half Marathon is a scenic 13.2-mile trail race held annually in the Marin Headlands near Mill Valley, California. Celebrating its third year in 2025, the event features a challenging course with nearly 2,000 feet of elevation gain, showcasing stunning singletrack trails, sweepi..

Reservoir Dogs Trail Run, held in Orinda, CA on October 4, 2025, features three distances—10K, Half Marathon, and 35K—starting and finishing at the San Pablo Reservoir Recreation Area in EBMUD land. This race was the first to completely circumnavigate Briones Reservoir on permit trails, offering tre..

Star City San Bruno Mountain Half Marathon & 5K, organized by the Excelsior Running Club, takes place in Brisbane, CA, on the San Bruno Mountain trails. The course is 93% on trail with about 2,400 feet of elevation gain, including a single-track downhill and sweeping views of the Pacific, Bay, and S..

The Women's Headlands Half Marathon is a trail running event held in the scenic Marin Headlands near Mill Valley, California. This race features a brand-new half marathon course that highlights the area's stunning singletrack trails, challenging climbs, and exhilarating descents, offering runners a..

Run by the Sea is an annual running event held at Wilder Ranch State Park in Santa Cruz, California. Scheduled for October 5, 2025, the race offers three distances: a 4K run/walk, a 12K run, and a half marathon. The courses primarily follow flat, packed dirt trails along the scenic coastal bluffs of..

The Mt. Umunhum Trail Conquest-Fall is a trail running event held at Almaden Quicksilver County Park in San Jose, California. The race offers multiple distances including a 5K, 7 Mile, Half Marathon, 30K, Trail Marathon, and 50K.The longer courses venture into the scenic Sierra Azul Open Space Prese..